Large-scale irregularities of electron concentration in the southern magnetic anomaly area according to Intercosmos 19 satellite data

Using Intercosmos 19 satellite topside sounding data, a type of complex ionogram for which the lowest frequency of the radio-wave which has passed through the ionosphere is smaller than the greatest frequency of the radio-wave reflected from the ionosphere is considered. (Under normal conditions these frequencies are identically equal.) A mechanism is suggested by which radio-waves transmitted by the satellite propagate over 3000 km in the topside ionosphere in the presence of inclined large-scale plasma structures, which can explain the main features of such ionograms.The space-time distribution of this phenomenon on a global scale is analysed. It is shown that it manifests itself mainly in the local winter, in the daytime and in the Southern Hemisphere. It is hypothesized that these large-scale irregularities are formed in the vicinity of the South Atlantic magnetic anomaly and then move westward.